Equalizing device for extension tables



E. H. COOK EQUALIZING DEVICE FOR EXTENSION TABLES Filed July 1.7, 1925 INVENTOR L1H. COOK m 760 ATTORNEYS Q w o o a n l a o 9 9 f. G

June 25, 1929.

Patented June 25, 1929.

UNl'lED- STATES PATENT OFFICE.

EARL HERBERT 000K, or warnnrown, WISCONSIN.

EQUALIZING DEVICE FOR EXTENSION TABLES.

Application filed July 17, 1925. Serial No. 44,323.

My invention relates to improvements in equalizing devices for extension tables, and t consists in the combinations, constructions, and arrangements herein described and claimed.

An object of my invention is to provide an equalizing device of the character described for maintaining the extended portions of an extension table at equal distances from its central support thereby properly distributing the weight of theinembers with respect to the central support. It should be noted of course that my improved equalizing device is not limited in its application to tables having a central support, but also to tables having supports at eachof the extended portions as well as central supports.

A further object of my invention is to provide an equalizing device of the character described in which particularly novel means is employed for maintaining the three cooperating members of the equalizing device against inoperative disengagement with one another.

A further object of my invention is to providean equalizing device of the character described that is simple in construction, compactin form, durable, and thoroughly practical for the purpose intended.

Other objects and advantages will appear in thefollowing specification, and the novel features of the invention will he particularly pointed out in the appendedclaim.

My invent-ion is illustrated in the accompanying drawings,forming part of this application, in which Figure 1 is a bottom plan View of an extenw sion table equipped with myimproved equalizing device, i

Figure 2 is an enlarged plan view of one of the equalizing units,

Figure 3 is an enlarged sectional View along the line 33 of Figure 2, and

Figure 4 is a fragmentary perspective view of a part of the device illustrated in Figure 2.

I11 carrying out my invention I make use of the ordinary type of extension table having two principal parts A and B, which are intended for movement apart from one another to permit the introduction at will of one or more inserts placed between the normally abutting edges 1 of the parts A and B.

My improved equalizing device forms a two-fold function of maintaining a central support 2 beneath the center of gravity of the table at all times as well as furnishing a means for supporting the parts A and B upon the central support 2.

This equalizing device consists of two units and 1) disposed parallel with one another and having portions thereof secured to the member A of the table and other portions secured to the member B. The units G and D are identical in construction, one of which is shown in detail in Figure 2.

This unit consists of a central block 3 and a pair of blocks 4 and 5 disposed parallel with one another and secured against lateral movement relative to one another by the provision of metal runners 6 embedded in the blocks 3 and 5 which engage with integral portions 7 of the blocks 4 and 3 respectively, which portions 7 are greater in diameter at their outermost end so as to preclude lateral movement of the runners 6. The runners 6 are engaged primarily with the portions 7 bymoving the blocks longitudinally toward one another and thusengaging the runners with the portions 7 over the ends of the portions 7. When once the blocks 3, 4 and 5 are assembled, as shown in Figure 2, it is impossible to move the blocks laterally, yet longitiulinal movement of the blocks is unobstructed. The runners 6 also serve as guides for maintaining the upper surfaces of the blocks 3, i and 5 contiguous.

The structure indicated at 6 and 7 is well known in the extension table art. The block 3 is provided with a recessed portion 8 in the bottom wall thereof and at the mid-point of the block. A gear train consisting of three pinions 9, 10 and 11 in mesh with one another rotatably mounted upon the block 3 by means of shafts 12 is disposed between the racks 13 and 14. The pinion 9 is inmesh with the teeth of the rack 13 and the-pinion 11 is :in mesh with the teeth of the rack 14. The shafts 12 are secured against movement at their upper ends by engagement with a plate 12 which is fixed to the block 3 at 12". The entire gear train formed of the pinions including the plate 12 is disposed Within the recessed portion 8 of the block 3.

Two lengths of angle iron 13 and 14 are socured by means of screws 15 to the lower and adjacent edges of the blocks 1 and 5 respectively. That portion of the irons 13 and 14; disposed at the adjacent side walls of the blocks t and 5 is embedded in the blocks by providing a suitable recess, see Figure 3, so

' after refer to the irons spectively and are disposed at opposite ends of the blocks 4 and 5 respectively. Each of the irons 13 and 14 are provided with rack teeth formed by punching angular openings 17 through the wall 16 of the irons. In Figure 4 I have shown one of the irons in perspective to more clearly show the disposition of the openings 17.

The units C and D are secured to the members A and B of the table by projecting screws 18 through openings 19 provided in the blocks 4 and 5 at that end opposite to the end occuied by the angle irons 13 and 14 respectively. or the purpose of simplicity I shall herein- 13 and 14 as racks 13 and 14. v

A platform 20 having substantially the shape of the letter H is secured at 21 to the i block f the units C and D and the upright central support 2 is secured to the member From the foregoing description of the various parts of the device, the operation thereof may be readily understood. When the parts A andB of a table equipped with my improved equalizing device are moved apart from one another as for instance the movementof the part B from the member A, as shown in Figure 1, the blocks'4 and 5 which are fixed securely to the members B and A respectively must therefore move relative to one another also. This movement of the blocks 4and 5 relatively apart from one anotherc'auses rotation of the pinions 9, 10 and 11 which are fixed except for rotative movement to the block 3. The effect of the rotative movement of the pinions caused by en agement of the toothed portion of the rae s 13 and 1 4 therewith'will be to maintain the block 3 at an equal distance from the, blocks 4 and 5,

7 thus the platform 20 bearing the central support 2 will be disposed at a mid-point between the parts A and B regardless of which of the parts actually moves, or whether both of the parts moved with respect to the supporting surface or floor upon which the table is disposed.

The principal feature of my invention is the peculiar structure of the racks 13 and 14 which preclude beyond all possibilities the disengagement of the pinions 9 and 11, respectively, therefrom. In the present type of equalizing devices, it is not uncommon to have the pinions temporarily disengaged from one of the racks. This will throw the entire equalizing device out of permanent ad'ustment and cannot function properly unti the blocks are placed in their proper relative positions and the pinion reengaged with the rack.

As the parts A and B are also moved apart from one another quickly and the device must necessarily stand a great deal of abuse, the racks because of the angle structure greatly strengthen the operative parts of the units C and D and therefore are competent to stand such abuse.

It should be understood that while I have shown an embodiment of my invention in the drawings employing a gear train consisting of three pinions that a gear train of three five or seven pinions or even, if desired, may be used for the purpose of providing structure applicable to a table in which the spread is unusually great. It should also be understood that one pinion may be employed which would then engage with the racks 13 and 15 directly.

I claim:

In a device of the type described a stationary block, a retaining member rigidly mounted upon said stationary block and spaced away therefrom, a pinion rotatably disposed between said block and said retaining memher, a movable block, a gear rotatably disposed between said stationary block and said retaining member and in mesh with said inion, and means carried by said movable b ock for operatively connecting said movable block with said gear, said means comprising an angle member having a plurality of spacedapart openings roviding portions a-rran d to mesh with said gear, said movable blockqi eing provided with an elongated groove for receiving the teeth of said gear.

EARL H. COOK. 

